NEW HAVEN, Conn. (CBS/WFSB/AP) The trial of Connecticut home invasion suspect Steven Hayes, charged in killing three members of the Petit family, will continue with testimony from a fire marshal, following testimony from two medical examiners Thursday.

According to CBS affiliate WFSB, the medical examiners took the stand Thursday to explain to jurors how Jennifer Hawke-Petit and her daughters, 17-year-old Hayley and 11-year-old Michaela died.

"I think we all knew the girls went through some really unpleasant things," Hawke-Petit's sister Cynthia Hawke-Renn told WFSB. "Didn't know all details, but we aren't surprised what the evidence shows. Just a sad day."

The testimony of Chief Medical Examiner Raymond Carver came a day after that of Connecticut State Police Detective Anthony Buglione, who detailed his interview with Hayes following his 2007 arrest, says WFSB.

Buglione claimed that Hayes was emotionless as he detailed the break into the Petit's home in Cheshire.

Hayes allegedly described without flinching how he and his partner-in-crime, Joshua Komisarjevsky, tied up the family members, sexually assaulted the mother and the youngest daughter, stole money and jewelry, and set the house on fire while the Petit women were still inside.

"The whole thing is disturbing," a Petit family friend Ron Bocchi told WFSB. "It's disturbing to the people who don't even know the family."

Hayes is believed to be the mastermind behind the 2007 Cheshire, Conn. home invasion that claimed the lives of three members of the Petit family: Jennifer Hawke-Petit, Haley, 17, and Michaela, 11. Komisarjevsky is awaiting trial.